

THE DEHISCENCE OF ANTHERS BY APICAL PORES. 



183 



have a very good representative of this type, although the 

 anthers offer some peculiarities of structure. (Ten species; 

 all but one, which is found in Lower Guinea, are American ; 

 1 very similar to and possibly identical with a South Ameri- 

 can form occurs in eastern North America, 1 occurs in 

 Cuba, and the others in Brazil, Peru and Guiana. Brazil 



has six species.) 



Rapateaceae. 



The Rapateaceae is a family of six genera and about 19 

 species in tropical South America. Its position in this 

 <n*oup is somewhat questionable on account of the moder- 

 ately long perianth tube formed by the lower portion of 

 the segments. The limb, however, is patent, the anthers 

 basifixed and linear and shedding their pollen through 

 terminal pores or a single terminal pore, sometimes pro- 



prolongation 



the anther. 



Commelinaceae 



The Commelinaceae is represented by two genera besides 

 the highly interesting Cochliostema to be described later. 

 Cartonema (5 or 6 species confined to tropical Australia) 

 shows a considerable range of form in the structure of the 

 anther. In some species, dehiscence is by longitudinal 

 slits ; dehiscence by pores seems to be in a less perfected 

 state than in the tropical American Dichorisandra (about 

 27 species, almost exclusively Brazilian). This genus is a 

 highly interesting and very characteristic representative of 



Solanum 



minor 



differences, a considerable degree of 

 uniformity prevails in the floral structure of the Comme- 

 linaceae. The petals are patent, except in about 3 genera 

 in which they are unguiculate and united into a usually 

 narrow tube, and 1 in which the perianth is tubular 

 below, but even here the limb is generally patent. The 

 basifixed anthers show a wide range of form, while the 



